Method and apparatus for feeding a sheet metal web

ABSTRACT

Method and apparatus are provided for precise feeding of a heavy and springy sheet metal web to and through a press for blanking and drawing metal cups therefrom. A preferred embodiment has a pair of fixed pneumatically actuated gripping members positioned along the edge of the web path and a corresponding pair of movable pneumatically actuated gripping members similarly positioned. The movable gripping members grip the web edges when moving from first positions to second positions downstream. The fixed gripping members grip the web as the movable gripping members return to their first positions. Operation of the gripping members is timed with the reciprocating operation of male blank-draw punches vis-a-vis cooperating female dies.

United States Patent [191' Miller METHOD AND APPARATUS FOR FEEDING A SHEET METAL WEB [58] FieldofSearch 113/113 R, 113 A, 113 C; 72/361, 423, 422; 214/1 F, l S; 226/150; 83/206 56] References Cited UNITED STATES PATENTS 831,765 9/1906 Beyer 113/113 2,012,423 8/1935 Ferris 738,103 9/1903 Devine 2,467,740 4/1949 Haller 3,123,270 3/1964 Olson 3,157,334 11/1964 Bunnell et a1 3,429,493 2/1969 Lehmann 226/150 Primary Examiner-Richard J. Herbst 5 7 ABSTRACT Method and apparatus are provided for precise feeding of a heavy and springy sheet metal web to and through a press for blanking and drawing metal cups therefrom. A preferred embodiment has a pair of fixed pneumatically actuated gripping members positioned along the edge of the web path and a corresponding pair of movable pneumatically actuated gripping members similarly positioned. The movable gripping members grip the web edges when moving from first positions to second positions downstream. The fixed gripping members grip the web as the movable gripping members return to their first positions. Operation of the gripping members is timed with the reciprocating operation of male blank-draw punches vis-a-vis cooperating female dies.

5 Claims, 3 Drawing Figures PATENTED FEBZS I974 saw 2 0F 2 METHOD AND APPARATUS FOR FEEDING A SHEET METAL WEB BACKGROUND OF THE INVENTION This invention relates generally to the blanking and drawing of metal cups from a sheet metal web, and, in particular, to a method and apparatus for feeding a sheet metal web to and through a blanking and drawing press.

As used herein, the term blank refers to the cutting of a generally flat circular metal piece from a metal web, normally of aluminum, steel or tin-plated steel sheeting.

The term drawing refers to an operation whereby the peripheral area of a flat circular metal. blank is turned up generally in a perpendicular direction to the sheet and simultaneously smoothed by means of a drawing punch and die to form a cup.

Typically, blanking and drawing of one or more cups are accomplished in a press by the reciprocating movement of one or more male punches with tespect to corresponding female dies. The sheet metal web from which cups are made is fed between the male punches and female dies when they are disengaged.

A blanking-drawing operation whereby a cup is formed from a sheet metal web is an important initial metal-working step in a method of making metal container bodies of the type having integral sidewalls and bottoms. Containers of this type are known in the trade as two piece containers. For years, such containers have been made primarily of relatively light and flexible metals, such as aluminum. Prior art metal web feeding devices, such as dual roller systems having two peripherally-adjacent oppositely-rotating rollers which advance a metal web therebetween either intermittently or continuously (with accumulated slack intermittently advanced, when punches and dies are disengaged), may be used with some success with light and flexible metals such as aluminum. Recently, however, there have been attempts to make such containers of stronger, heavier, springier metals such as steel and tinplated steel. Prior art metal web feeding'methods and devices have not been readily adaptable to heavier metals. There has been an increased need for an improved web feeding method and apparatus.

Other problems with various prior art metal web feeders relate to accuracy and speed of the web feed. Accuracy is particularly important when a pattern of blanks with minimal waste material therebetween is to be cut from the web. In a rapidly reciprocating press a rapid web advancing operation, without any web slippage or other loss of accuracy, is required.

This invention provides a method and apparatus which use a unique positive feed technique which accurately and rapidly feeds sheet metal webs, including webs of relatively heavy metals. The apparatus includes fixed and movable gripping members which alternate in gripping a metal web. When movable gripping members are activated to grip the web, fixed gripping members are deactivated. The movable grippers advance the web downstream. Thereafter, the movable grippers release the webs as the fixed grippers are activated to grip the web. The deactivated movable grippers move back upsteam before the cyclical operation is repeated. Operation of the grippers is timed to be coordinated with the normal reciprocating press movements.

A primary object of the invention is to provide a sheet metal web feeding apparatus and method for use in a blank-draw press which overcome problems of prior web feeders.

Another object of the invention is to provide a metal web feeding apparatus and method which provide successful feeding of relatively heavy metal webs, such as steel webs, which are used in cup manufacture.

Yet another object of the invention is to provide a metal web feeding apparatus and method which provide good accuracy and speed in web feeding to and through a blank-draw press, such as is used in the manufacture of can bodies.

A further object of the invention is to provide a method and apparatus for periodically feeding a positive predetermined length of a sheet metal web to and through a blank-draw press used in making cups from the web.

These and other important objects will become apparent from the detailed descriptions herein and from the drawings wherein:

FIG. 1 is a plan view just above the web path level of a blanking and drawing press including the apparatus of this invention.

FIG. 2 is a side sectional view taken at Section 2-2 as shown in FIG. 1.

FIG. 3 is a sectional view of a gripping member as indicated by Section 3-3 in FIG. 2.

Referring now in detail to the drawings, wherein like parts are indicated by like numerals, a portion of a blanking and drawing press 20 is shown. That portion of press 20 which is shown contains female dies 22 which cooperate with reciprocating punches not shown. The male punches ride on an overhead structure not shown supported by posts 72. Dies 22 are affixed to a base structure including bottom plates 24 and bolster plate 26. Flush with tops 28 of dies 22 are various pieces which form a stock plate 30 over which a sheet metal web is fed. Stock plate 30 forms a web sup port means. The direction of advance of a sheet metal web is indicated by the arrows in FIGS. 1 and 2.

Preferably, a sheet metal web is supplied from a coil, not shown in the figures, to a web entry side 32 of press 20. The web progresses intermittently over stock plate 30 through press 20 while the male punches are disengaged from female dies 22. The web advances from web entry side 32 to an opposite web exit side 34 after which the remainder of the web is scrapped. The web forms a web path having edges 36 across said press 20. Cups blanked and drawn from the web will exit from press 20 in a direction normal to the direction of web travel. The feeding of metal web from the coil through press 20 is achieved and controlled by the apparatus of this invention.

The embodiment of the web feeding apparatus shown in the drawings has a pair of fixed sheet gripping members 38 connected along the web path at path edges 36 to stock plate 30, both at the web entry side 32 and web exit side 34 of press 20.

FIG. 3 illustrates one of these sheet gripping members 38 in cross section. The gripping member forms, in effect, a cylinder 40 containing a piston 42 which is pneumatically actuated. Cylinder 40 defines ports 44 and 46 which are connected to a source of air pressure not shown. When air pressure is raised in a chamber 48, piston 42 is displaced downwardly against the edge of web 50, which is inserted in slot 74 under a portion of gripping member 38, pinning web 50 to stock plate 30. When pressure is increased in chamber 52 and reduced in chamber 48, pistion 42 is displaced upwardly releasing web 50 from the grip of gripping member 38 and allowing it to slide within slot 74. Control and timing of the gripping members will be referred to further herein.

Corresponding to each of the pairs of fixed gripping members 38 are movable sheet gripping members 54, which are mounted to ride on rails 56 secured below stock plate 30. Movable gripping members 54 move reciprocatingly from first positions indicated by solid lines to second positions generally indicated by phantom lines. Their movement is within cut out portions 58 defined by stock plate 30 such that they are aligned with their corresponding fixed gripping members 38 along the web path. Each of the movable gripping members 54 has a pneumatically actuated piston like that of fixed gripping members 38. However, the pistons in movable gripping members 54 pin the web against a movable backing member which forms a part of each movable gripping member 54.

The movement of movable gripping members 54 is accomplished by means of a rotating cam 60 linked by a chain and sprocket system 62 to the press drive shaft 64 or other driving shaft in press 20. Cam follower 66 is linked to movable gripping members 54 on web entry side 32 of press 20 by mechanical linking means 68 as shown. Movable gripping members 54 on web exit side 34 are also driven by cam 60 through connector bar 70 which runs the length of press 20 to mechanical linking means similar to means 68 on web entry side 32. Cam 60 is designed to provide movement of movable gripping members 54 when the aforementioned punch and die combinations are disengaged.

Movable gripping members 54 are activated to grip the web as they move from the first positions (solid lines) to the second positions (phantom lines). While movable gripping members 54 are moving, fixed gripping members 38 are deactivated to release the web, allowing it to slide therethrough. After movable gripping members 54 reach their second positions, fixed gripping members 38 are activated to grip the web and movable gripping members 54 are deactivated to release the web. In this condition movable gripping members return from their second positions to their first positions by the action of cam 60 and associated parts. Thereafter, movable gripping members 54 are activated and fixed gripping members 38 are deactivated and the cycle is repeated.

The activation and deactivation of the gripping members in this preferred embodiment is accomplished by solenoid-controlled air valves, not shown, within air lines communicating with ports 44 and 46. The solenoids are operated in timed response to movements of the reciprocating male punches by switch means, not shown, which provide electrical signals thereto.

Various other activation and deactivation means could be used in this invention. Further, various other means could be used to achieve the necessary movements of movable gripping members 54. Such alternative means would be known by persons skilled in the art who have been made familiar with this invention.

While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.

I claim:

1. In a press for blanking and drawing cups from a continuous sheet metal web fed along a path therethrough of the type having support structure, web support means connected thereto, female dies mounted to said support structure, cooperating reciprocatin male punches, press drive means for said punches, and feeding means to advance said continuous metal web between said dies and cooperating punches when said punches are disengaged from said dies, the improvement wherein said feeding means comprises: a source of continuous metal web of a given width to be fed to said path; fixed web gripping members connected along said web path and comprising a movable clamping piece which can be activated to sandwich said web against said web support means; movable web gripping members slidably mounted on rails connected to said web support means along said web path to move reciprocatingly within cut-out portions defined in said web support means and aligned with said rails from a first position along said path to a second position downstream along said path whereby movable and fixed gripping members are generally on the same line along said web, said movable gripping members comprising a base with a surface generally coplanar with said web support means and a movable clamping piece which can be activated to sandwich said web against said surface; means to move each said movable gripping member cyclically from said first position to said second position and then from said second position to said first position; means activating each said movable gripping member to grip said web as said movable gripping member moves from said first position to said second position and deactivating said movable gripping member to release said web as said movable gripping member moves from said second position to said first position; and means activating each said fixed gripping member to grip said web as said movable gripping member moves from said second position to said first position and deactivating said fixed gripping member to release said web as said movable gripping member moves from said first position to said second position.

2. In a press for blanking and drawing cups from a continuous sheet metal web fed along a path therethrough, of the type having support structure, web support means connected thereto, female dies mounted to said support structure, cooperating reciprocating male punches, press drive means for said punches, and feeding means to advance said continuous metal web between said dies and cooperating punches when said punches are disengaged from said dies, the improvement wherein said feeding means comprises:

a source of continuous metal web, of a given width,

to be fed to said path;

at least one pair of fixed web gripping members connected along opposite edges of said web path, each of said fixed gripping members comprising a movable clamping piece which can be activated to sandwich said web against said web support means;

at least one pair of movable web gripping members mounted along opposite edges of said web path to move reciprocatingly from first positions along said path to second positions downstream along said path, said movable gripping members comprising a 5 base with a surface generally coplanar with said web support means and a movable clamping piece which can be activated to sandwich said web against said surface;

means to move said movable gripping members cyclically from said first positions to said second positions and then from said second positions to said first positions;

means activating movable gripping members to grip said web as said movable gripping members move from said first positions to said second positions and deactivating said movable gripping members to release said web as said movable gripping members move from said second positions to said first positions; and

means activating said fixed gripping members to grip said web as said movable gripping members move from said second positions to said first positions and deactivating said fixed gripping members to release said web as said movable gripping members move from said first positions to said second positions.

3. The apparatus of claim 2 wherein said press has a web entry side and an opposite web exit side and wherein a pair of said fixed gripping members and a corresponding pair of movable gripping members are located on said web entry side of said press.

4. The apparatus of claim 3 wherein an additional pair of said fixed gripping members and a corresponding pair of movable gripping members are located on said web exit side of said press.

5. The apparatus of claim 2 wherein said movable gripping members are slidably mounted on rails connected to said web support means and extending between said first and second positions and wherein said web support means defines cut-out portions aligned with said rails wherein said movable gripping members reciprocate, whereby movable and fixed gripping members are generally on the same line along said web. 

1. In a press for blanking and drawing cups from a continuous sheet metal web fed along a path therethrough of the type having support structure, web support means connected thereto, female dies mounted to said support structure, cooperating reciprocating male punches, press drive means for said puNches, and feeding means to advance said continuous metal web between said dies and cooperating punches when said punches are disengaged from said dies, the improvement wherein said feeding means comprises: a source of continuous metal web of a given width to be fed to said path; fixed web gripping members connected along said web path and comprising a movable clamping piece which can be activated to sandwich said web against said web support means; movable web gripping members slidably mounted on rails connected to said web support means along said web path to move reciprocatingly within cut-out portions defined in said web support means and aligned with said rails from a first position along said path to a second position downstream along said path whereby movable and fixed gripping members are generally on the same line along said web, said movable gripping members comprising a base with a surface generally coplanar with said web support means and a movable clamping piece which can be activated to sandwich said web against said surface; means to move each said movable gripping member cyclically from said first position to said second position and then from said second position to said first position; means activating each said movable gripping member to grip said web as said movable gripping member moves from said first position to said second position and deactivating said movable gripping member to release said web as said movable gripping member moves from said second position to said first position; and means activating each said fixed gripping member to grip said web as said movable gripping member moves from said second position to said first position and deactivating said fixed gripping member to release said web as said movable gripping member moves from said first position to said second position.
 2. In a press for blanking and drawing cups from a continuous sheet metal web fed along a path therethrough, of the type having support structure, web support means connected thereto, female dies mounted to said support structure, cooperating reciprocating male punches, press drive means for said punches, and feeding means to advance said continuous metal web between said dies and cooperating punches when said punches are disengaged from said dies, the improvement wherein said feeding means comprises: a source of continuous metal web, of a given width, to be fed to said path; at least one pair of fixed web gripping members connected along opposite edges of said web path, each of said fixed gripping members comprising a movable clamping piece which can be activated to sandwich said web against said web support means; at least one pair of movable web gripping members mounted along opposite edges of said web path to move reciprocatingly from first positions along said path to second positions downstream along said path, said movable gripping members comprising a base with a surface generally coplanar with said web support means and a movable clamping piece which can be activated to sandwich said web against said surface; means to move said movable gripping members cyclically from said first positions to said second positions and then from said second positions to said first positions; means activating movable gripping members to grip said web as said movable gripping members move from said first positions to said second positions and deactivating said movable gripping members to release said web as said movable gripping members move from said second positions to said first positions; and means activating said fixed gripping members to grip said web as said movable gripping members move from said second positions to said first positions and deactivating said fixed gripping members to release said web as said movable gripping members move from said first positions to said second positions.
 3. The apparatus of claim 2 wherein said press has a web entry side and an opposite web exit side and wherein a pair of said fixed gripping members and A corresponding pair of movable gripping members are located on said web entry side of said press.
 4. The apparatus of claim 3 wherein an additional pair of said fixed gripping members and a corresponding pair of movable gripping members are located on said web exit side of said press.
 5. The apparatus of claim 2 wherein said movable gripping members are slidably mounted on rails connected to said web support means and extending between said first and second positions and wherein said web support means defines cut-out portions aligned with said rails wherein said movable gripping members reciprocate, whereby movable and fixed gripping members are generally on the same line along said web. 